Weed control in lentil is difficult because lentil is a poor competitor withweeds and few POST broadleaf herbicides are available.Imadazolinone-tolerant lentils have more herbicide options, but the optimumtiming for herbicide application is not known. The critical period of weedcontrol (CPWC) is the period in a crop's life cycle when weeds must becontrolled in order to prevent yield loss. The objective of this researchwas to determine the CPWC for lentil. We made lentil remain weedy orweed-free from 0 to 11 aboveground nodes to investigate the durations ofweed interference and weed-free period, respectively. It was found thatlentil has a CPWC beginning at the five-node stage and continuing to the10-node stage. There was an inverse relationship between weed biomass andlentil yield; that is, lentil yield was highest when weed biomass isminimal. We propose that the CPWC begins when weeds start to accumulatesignificant biomass and ends with crop canopy closure. Therefore, tomaximize lentil yields, growers should consider using a POST residualherbicide that can control weeds during the CPWC.
